This invention relates to a receiving device used in a mobile radio communication system such as a personal handy-phone system.
It is known that a mobile radio communication system such as a personal handy-phone system (PHS) comprises a base station and a plurality of mobile stations each of which communicates with the base station. Inasmuch as the base station is connected to each of the mobile stations by a radio channel in the radio communication system, the transmission signal on the radio channel may be inevitably subjected to fading. As a result, error may occur in the transmission signal by fading. In order to detect the error in the transmission signal at a reception side, the transmission signal may carry an error detecting code.
It will be assumed that a base station transmits the transmission signal to a specific one of the mobile stations by the radio channel in a conventional personal handy-phone system. The transmission signal comprises a plurality of signal frames each of which may have a speech signal and an error detecting code. The specific mobile station comprises a receiving device for receiving the transmission signal as a reception signal. The receiving device demodulates the reception signal into a demodulated signal to detects an error at each of signal frames in accordance with the error detecting code. When the error exists in a particular one of the signal frames, the receiving device produces a muting signal which may be outputted from a loudspeaker. When the error does not exist in the particular signal frame, the receiving device outputs the speech signal from a loudspeaker.
As readily understood from the above description, the muting signal is outputted from the loudspeaker in each of the mobile stations when the error exists in the particular signal frame. Therefore, it is difficult to stably receive the speech signal in the receiving device used in each mobile station of the conventional personal handy-phone system.